1. Field of the Invention
The present invention relates to an imaging apparatus such as a camera, and more particularly, to a technology for correcting lateral chromatic aberration and distortion of an image.
2. Description of the Related Art
Recently, demands for acquiring a clear image of an object in a low-illuminance environment by an imaging apparatus, such as an in-vehicle back monitor, is growing. To fulfill this demand, an optical filter that can transmit light with a wavelength in the infrared region (infrared light) as well as light with a wavelength in the visible region (visible light) are actively developed. Such an optical filter is distinguished from an infrared cutoff filter that is typically used for reducing noise in the image of the object. A conventional optical filter is disclosed in, for example, Japanese Patent Application Laid-open No. 2007-150826 and Japanese Patent Application Laid-open No. H11-316405.
Specifically, the conventional optical filter allows infrared light to pass through a predetermined area of the optical filter towards an imaging plane of an imaging device without through an infrared cutoff filter, so that an image of an object in an area corresponding to the predetermined area can be formed on the imaging plane with increased light intensity. Therefore, a highly-clear image of the object can be obtained even in a low-illuminance environment.
Recently, demands for enabling a wide angle of view in the imaging apparatus are also increasing. Because lateral chromatic aberration in a captured image increases as the angle of view is widened, an optical system needs to be designed so that the lateral chromatic aberration can be prevented. However, designing of such an optical system leads to complicated processes, resulting in increasing costs.